> We can use nr_cpu_ids instead of NR_CPUS.> For a machine like 4096 CPUs, such an amount of memory is like a> peanut :)

It's not peanuts if you're dealing with a distro kernel that's essentiallyforced to compile with NR_CPUS=<some moby integer>, but booting on a single ordual core system with possibly not even 1G of memory.